Machine tool cutting speed indicator



April 1'5, 1947. R, H` CLARK www@ MACHINE TOOL CUTTING SPEED INDICATR Filed Dec. 14, 1944 2 Sheets-Sheet HTMRNEY@ may? s 1%? Ra H. CLARK MACHINE TOOL CUTTING SPEED INDICATOR Filed Dec. 14, 1944 2 SheetsSheet 2 1N VEN 'Patented Apr. 415, 1947 enano,

H. Clark,.Solon, Ohio, assigner to The Warner & Swasey Company, Clevelandt Ohio, a

corporation of Ohio Application December 14, 1944, serial No, 568,193

ionims. (ci. 117-311) 1 This invention relates to a machine tool an more particularly to the provision of an electrical indicating mechanism used in conjunction with a movable part of a machine tool.

An object of the invention is to provide an electrical indicating mechanism for use with a machine tool to facilitate the operation and improve the eiiiciency thereof.

Another object is to provide in a machine tool having a part which is movable at different rates and means for selecting or preselecting such difwith suitable clutch means i5 whereby said shaft A ferent rates of movement of said part, an electrical indicating mechanism which is responsive to the operation of said selecting or preselecting means. y

Another object is to provide an improved electrical indicating mechanism for indicating the surface or cutting speeds of a rotating work piece or a. cutting tool and in relation to different diameters. y

Further and additional objects and advantages will become apparent hereinafter during the de scription of embodiments of the invention which is to follow.

Referring to the accompanying drawings, Fig. l illustrates an application to a machine tool of an electrical indicating mechanism ernbodying the invention, certain parts of the machine tool being diagrammatically illustrated to bring out the relationship thereof to the indicatlng mechanism, while A Fig. 2 depicts adiiferent form of electrical indicating mechanism also embodying the invention. i Although the electrical indicating mechanisms may be operatively associated with various types of speed selectors for a movable part of a machine tool the said mechanisms are, for purposes of illustrationshown as operatively connected with the arrangement for selecting or preselecting the different speeds of the work spindle of a lathe and which arrangement is fully disclosed in Patent No. 2,068,552, issued to Max E. Lange, January i9. 193'?.

Pteierring to Fig. l, the change speed transmission drive for the work spirdle l0 is indicated somewhat diagrammatically. it will be understood that the work spindle I0 is rotatabl`y-supported 4in the headstock of the machine tool and is driven from the shaft Il, inl-this instance, at any one of twelve different speeds through gearing which includes a three-step shiftable gear con@ le, rear two-step shift/able gear cone i3 and a iront two-step shiftable gear cone H, as will be Well understood and as is fully disclosed in said Lange patent. The shaft il is provided can be connected to the change speed gearing for forward or reverse drive thereof or can be dlaconnected therefrom.

In the said Lange patent there is disclosed an indexible shaft I6, suitably supported in 'the headstoclr or in some other part of the machine and mounted on said shaft to rotate with it but capable of moving axially relative thereto are spools Il and i8 and which spools are provided on their adjacent faces with series of long and t short projections, short and long projections and projections of equal length, correlated to the different speeds ci the spindle. Elements I9, 2li and 2| are located intermediate the adjacent faces of the spools il and i8 and are operatively connected respectively, with the three-step gear cone i2, the rear two-step gear cone I3 and the' front two-step gear cone I4 by suitable mechanisrn represented diagrammatlcally in the drawing by the dash and dot lines. `The spools i1 and i8 are moved toward and away from each other axially of the shaft I6 with an equalized movement by mechanism not shown, since it is proper positions correlated to the spindle speeds,

after which they are moved toward each other to bring the series of projections into engagement with some or all oi' the elements i9, 20 and 2i to shift said elements and in turn to shift the gear cones of the transmission to obtain the sclected spindle speed. I

'I'he mechanism disclosed in the Lange patent for moving the spools toward and away from each other with an equalizerl movement is operatively connected with the mechanism which engages and disengages the clutch IE. The different spindle speeds may be selected after the clutch l5 has been disengaged at the end of one operative step in the work cycle or the spindle speedsv may be preselected, that is, the spools are brought to their separated positions and are indexed during one operative step of the were: cycle to the position corresponding to the spindle speed for that has been preselected for the rnexteoperative" step. This mode of selecting or preselecting the different spindle speeds is clearly disclosed in said 3 lange patent and need notbeexplained in greater detail herein.

The shaft i3 may indexed by means of a hand wheel or knob 22 fixed to the end of the shaft at the front of the headstock or it mayr be indexed by any other suitable means. The shaft i6 may have xed thereto a gear 23 which meshes with a gear 24 mounted on a stub shaft 25 rotatably supported by the headstock and having iixed thereto an indicating dial or drum 23 bearing indicia corresponding to the different spindle speeds in revolutions per minute, wherefore when the spools are indexed the dial or drum 23 will also be indexed to indicate in terms of spindle speeds the positions o! the spools. The dial or drum 23 may be provided with slots 21 and in which slots number blocks. representing the dfferent operative steps of the work cycle can be removably positioned. This latter arrangement is fully disclosed in Lange Patent No. 2,169,765, issued August 15, 1939.

Although the electrical indicating mechanism embodying the present invention is illustrated as used in conjunction with the selecting or preselecting arrangement disclosed in said Lange patents hereinbefore referred to, it will be understood that said electrical indicating mechanism be operatively associated with other forms or arrangements for selecting or preselecting the different rates of movement o! a movable part oi' a machine tool.

Referring to said Fig. 1, a rheostat Itx is operatlvely associated with the shaftl 'I3 and said rheostat comprises a resistance element 23 and a wiper 23 that coacts with the resistance elenient and is operatively connected to the shaft i3 to turn therewith. Consequently the indexing movement imparted to said shaft and to the spools I1 and I8 will also be imparted to the wiper 23 to vary its contacting position with respect to theresistance element 23 of the rheostat. Consequently the rheoetat will be adjusted automatically in accordance with the spindle speed selecting indexing movements imparted to the spools. The resistance element 23 has its ends electrically connected to electrical conduits and 3i which extend to a suitable source of regulated voltage power supply not shown. In other words, a constant voltage is impressed upon the resistance element 23 of the rheostat but the rheostat output voltage is varied in proportion and in correlation with the different indexed positions of the spools i1 and i3, that is, in relation to the different speeds of the spindle i3. The output voltage oi' the rheostat is impressed on a volt meter 32 oi' suitable and well known construction and said volt meter may be calibrated in spindle speeds, i. e., R. P. M. if desired. The resistance element 28 of the rheostat is directly connected by an electrical lead 33 with the terminal 34 of the volt meter 32. The wiper 29 of the rheostat R1 is electrically connected to an electrical lead 33 which is connected to one terminal of the resistance element 33 of a second rheostat R2, the other terminal of said resistance element 33 being connected with the lead 33 by the short electrical lead 31. wiper 33 which cooperates with the resistance element 33 and which wiper is electrically connected by a lead 39 with the terminal 40 of the volt meter 32. It will thus be seen that adjustment of the rheostat R2 will vary the output voltage of the rheostat R1 and that the voltage ultimately impressed on the Volt meter 4 32 will be the constant voltage supplied to the rheostat R1 reduced in accordance with the combined settings of the rheostats R1 andfR/f.

The rheostat R is provided with c scale 4I indicating the diameters in inches of the work mounted on the spindle I3 and said scale cooperates with the wiper 33; in other words. the rheostat R is calibrated in terms of work diameters in inches and said rheostat is manually adjustable by the operator of the machine. The pointer 42 of the volt meter 32 cooperates with a scale 43 representing the peripheral surface speed of the work piece in feet per minute, that is, the cutting speed or the tool in relation to the work piece. The volt meter is thun calibrated to indicate surface speed of the work piece in feet per minute.

Since a regulated or constant voltage is impressed on the rheostat R1 and this rheoctat is adjusted in accordance with the indexing movements imparted to the spindle speed selectoll or preselector mechanism the output voltage of the rheostat R1 will be in proportion to the spindle speed selected or preselected The oper*- ator before selecting or preselecting the spindle speed manually adjusts the rheostat R until the wiper 3l points to the graduation on the scale 4| representing in inches the diameter of the work piece. Inasmuch as the rheostat R is in the output circuit of the rheostat R1 a proportion only of the output of rheostat R1 is impressed on the volt meter 32. Inasmuch as the rheostat R1 proportions the voltage in accordance with spindle speeds (R. P. M.) and the rheostat Itn proportions the voltage in accordance with the work diameters, the ultimate voltage impressed l on the volt meter 32 will be proportional to the The rheostat R2 includes a movable surface speed of the work piece or the cutting speed of the tool moving relative to the work piece. The volt meter 32 will thus indicate thin the limits of its calibration for diiferent diameters of work the surface speed of the work or the cutting speed of the tool in feet Der minute.

The operator of a machine tool equipped with the electrical indicating mechanism described needs only to adjust the rheostat R. to the known work diameter, in addition to operating the speed selector in order to obtain a direct and accurate indication on the volt meter 32 of the surface orcutting speeds.

In Fig. 2 a different embodiment of the invention is shown. However, since this form differs from the form of Fig. 1, only in the use of a transformer having a plurality of taps extending from its secondary coil instead of the rheostat R1, the same reference numerals are employed in Figs. 1 and 2 to indicate identical parts.

The form illustrated in Fig. 2 utilizes a transformer T to vary the input voltage in relation to spindle speeds and the primary coil 44 thereof is connected to the electrical conduits 3l and 3l which extend to a suitable source, not indicated, of power supply. The secondary coil 43 of the transformer T is connected by the leads 33 to the terminal 34 of the volt meter 32 and by the lead 46 to the contact l1 of a multi-contact switch, the other contacts 41a of which are connected by tap leads 43 to the gikceesive turns of the secondary coil. A movable switch contact arm 43 is connected to the lead 3l and can be selectively engaged with the switch contact 4l or any of the other contacts 41a. The arm 43 is operatively connected with the shaft I3 and is moved selectively into various positions related l spindle speed and prior to the indexed positions of the spools l1 and Il and to .the selected or preselected spindle herein it will be understood that the invention is .susceptible of various modicatlons and adaptations within the scope of the appended claims.

Having thus described my invention, I claim:

l. In a'machine tool having a rotatable work spindle adapted to mount work pieces of difierent diameters to be machined by a cutting tool, a gear transmission adapted to be clutched to a power shaft and operatively connected to the spindle and including shiftable means for obtaining a plurality oi different predetermined gear ratios in said transmission to rotate said spindle at a corresponding number of different speeds, movable means operatively Iassociated V with said shiftable means and when moved to' one position indexible in correlation to the diilerent gear ratios to select or preselect the different spindle speeds and when moved to another position actuating said shittable means to obtain the selected or preselected spindle speed, voltage regconnected to said movby the indexing thereof ulating means operatively able means and adjusted to vary the voltage of regulating means, means for impressing a constant or regulated voltage. on the input sidev of said voltage regulating means, a volt meter calibrated in terms o! cutting speeds of a tool oper.. ating on the work piece, and electrical connec tions between said voltmeter and the output side of said voltage regulating means and including a second voltage regulating means calibrated in terms oi.' work diameters and manually the output side ofsaid adjusted to positions correlated to the diameter o! the work currently being machined to vary the voltage impressed on said volt meter, whereby said volt meter indicates cutting speeds in relation to work diameter instantly upon indexing of said movable means to select or preselect the to the movement o! said movable means to actuatc said shiitable means to obtain the selected or speed. l

2. A machine tool as denned in claim 1 and wherein both oi said voltage regulating means are in the form oi rheostats.

3. A machine tool as defined in claim 1 and wherein said nrst mentioned voltage regulating means includes a transformer having its primary coil connected to a supply source of constant or regulated voltage current while its secondary coil is connected to said second mentioned voltage regulating means and a terminal of said voit meter and to a plurality of switch contacts by tap leads. a movable switch arm adapted to engage said contacts and operatively associated with said movable means indexing thereof, an tween said arm and to` be moved by the electrical connection beanother terminal ot said preselected spindle volt meter andincluding said second voltage regulating means with said second inen-s tioned voltage regulating means in the form e! a, rheostat.

4. In a machine tool having a rotatable Wort:

spindle adapted to mount Work pieces of different diameters to be machined by a cutting tool, a gear transmission adapted to power shaft `and operatively connected to the spindle and including shiftable gear cones for obtaining a plurality of diierent predetermined gear ratlos in said transmission to rotate said `spindle at a corresponding number of different shaft having splined thereon a pair of spools movable toward and away from each other and provided on their adjacent faces with cooperating series of projections, actuating means for shifting said gear cones and having portions located intermediate said spools, said spools when moved to a separated position relative to each other being in correlation to the different shifted positions of said gear cones to select ent spindle speeds and when moved axially o! said shaft toward each ating means to move the same to shift the gear cones to obtain the selected or preselected spindle speed, voltage regulating means operatively cons nected to said shaft and adjusted by the indexing thereof to vary the voltage of the outputside ot said regulating means, means for impressing a constant or regulated voltage on the input side of said voltage regulating means, a volt meter cali brated in terms of cutting speeds of a tool oper ating on the work piece, and electrical connections between said volt meter and the output side of said voltage regulating means and including a rheostat calibrated in terms of Wort: diameters and manually adjusted to positions correlated to the diameter of the work currently being ma speeds, an indeiriblev chined to vary the voltage impressed on said volt The follow references are oi record in the file of this patent:

. s PAT-*mslm Number Name to 2,338,599 Ridgeway s Jan, 4. il 1,820,242 Nieman miwmmmss dus, 25, 193i. 2,193,077 Saxman .,..-.......s.. Mar. 12. 1940' Reeves Electric Remote Speed Indica-tor hir Reeves Pulley Co., Columbus, Indiana: 4 e: f

received in the Patent Onlce Library ber l1, 1943,

(Copy in Div. 42, class WVM-8116233 be clutched to a indexible with said shaft' or preselect the dition' other acting on said actu- 

